We conducted the coincidence measurement of $\alpha$ particles inelastically scattered from ${ }^{ 20}$Ne at $0^{ \circ}$ and decay charged particles in order to search for the alpha-particle condensed state. We compared the measured excitation-energy spectrum and decay branching ratio with the statistical-decay-model calculations, and found that the newly observed states at $E_x$ = 23.6, 21.8, and 21.2 MeV in ${ }^{ 20}$Ne are strongly coupled to a candidate for the 4$\alpha$ condensed state in ${ }^{ 16}$O. This result presents the first strong evidence that these states are the candidates for the 5$\alpha$ condensed state.
Categories: nucl-ex